AN

ESSAY

ON

THE FIRST PRINCIPLES

OF

NATURAL PHILOSOPHY :

WHEREIN

The Use of NATURAL MEANS, or SECOND CAUSES, in the Economy of the Material World, is demonstrated from REASON, EXPERIMENTS of various Kinds, and the TESTIMONY OF ANTIQUITY.

CONTENTS.

BOOK I.

Of the Mechanism of Nature.

1

PAGE

CHAP. I. The Introduction. Some occafional Reflec-

tions on the Prejudices of Philofophers. Apology for

the Author, with an Account of his Design. Two

different Systems of Philosophy briefly explained....

CHAP. II. A Reply to the principal Objections in Dr.

Clarke's Letters to Mr. Leibnitz....

CHAP. III. An Answer to a Physical Objection from

Sir Isaac Newton.....

CHAP. IV. An Examination of the Argument for a

Vacuum, deduced from Resistance and the Vis Iner-

tia in Bodies.....

CHAP. V. The Argument from Resistance proved to

be an Absurdity; as it implies that the Cause of

Motion must resist the Motion which it causes.
A

plain Experiment, to illuftrate and confirm the Au-

thor's Reasoning..

.16

34

.45

.59

CHAP.

CHAP. I. Attraction inquired into, from the Writings

of Sir Isaac Newton, and the most eminent of his

Followers

83

CHAP. II. An Attempt to settle the Question, Whe-

ther Attraction is the Cause or the Effect?..........94

CHAP. III. Attraction a material Force in the judg-

ment of some Authors; an immaterial Force in the

judgment of others; and sometimes both one and

the other in the judgment of the same Author......110

CHAP. IV. The Attraction of Gravity, understood

as an universal Property or Quality in the Parts of

Matter, has received no Proof from Geometry......130

CHAP. V. The Attraction of Gravity, understood as

an universal Property or Quality in the Parts of

Matter, is not agreeable to Experiment and Obser-

vation

CHAP. VI.

The Forces of Attraction and Projec-

tion, commonly called Central Forces, will not con-

sist with the Motion of the Planets, even upon the

suppofition of a Celestial Vacuum..

140

164

BOOK